Recently, digitalization has been remarkably widespread in the field of a color print using a color photographic printing paper. For example, a digital exposure system in which laser scanning exposure is used, has been rapidly spreading.
On the other hand, as a color print process other than one using a color photographic printing paper, technologies such as an ink jet process, a sublimation process, and a color xerography are advanced, and products applying these technologies are wide-spreading. Among these color print processes, a digital color print process using a color photographic paper is characterized in a high image quality, a high productivity, and a high fastness property of the image.
Particularly, in the remarkable widespread of the digital camera, if it were possible to receive digital camera recording media at a shop counter, and finish high-quality printing in a short period of time of about several minutes at a low cast, the superiority of color printing using color photographic printing paper would doubtlessly increase. Therefore, it is important to raise the rapid processing suitability of color-printing paper by using a printing apparatus, which is smaller in size and lower in costs while having high productivity.
To enhance the suitability of color photographic printing paper for rapid processing, various proposals have been made from the viewpoints of reducing each of exposure time, the time from the end of exposure to the beginning of processing, the time from processing to drying, and the like. Of these, reducing the time from processing to drying contributes the most to the rapid processing suitability. Decreasing the coating amount of silver and the thicknesses of coatings, though effective in achieving such reduction, results in the developed color densities being lowered. As such, this problem has awaited solution. Decreasing the thickness of a coating or the coating amount of a hydrophilic binder can lead to a condition in which the reach of oxidation products of a developing agent is beyond the thickness of a swollen color-forming layer, causing a drop in efficiency of dye-forming reaction with dye-forming couplers (hereinafter also referred to as couplers). Further, the oxidation products of a developing agent are consumed by color-mixing inhibitors in non-color-forming intermediate layers, and their concentration gradients become great; as a result, the proportion of oxidized developing agents that form no dyes in color-forming layers, is increased.
In a silver halide color photographic light-sensitive material, a non-color-forming intermediate layer containing a color-mixing inhibitor is generally disposed between emulsion layers having different color sensitivities, to prevent color impurity. The oxidized color-developing agent produced during development from emulsion grains present in the vicinity of the boundary surface between the emulsion layer and the intermediate layer has a high probability of being consumed by the neighboring color-mixing inhibitor, which is a contributing factor to reduced reaction efficiency of dye-forming couplers. In addition, it is known that migration of color-mixing inhibitors to other layers in advance of processing causes various detrimental effects, including decreased dye formation efficiency. Interlayer migration of color-mixing inhibitors is accelerated during storage under high humidity conditions, in particular, and the detrimental effects caused thereby become considerably serious when the coating amounts of hydrophilic binder and silver are reduced. Remedial steps to cope with these difficulties have therefore been desired.
Therefore, the idea of placing a spacer layer (a hydrophilic colloid layer containing neither a color-mixing inhibitor nor a silver halide emulsion) between a color-mixing-inhibitor-containing layer and a silver halide emulsion layer was conceived, and methods to incorporate a dye-forming coupler into a spacer layer, and convert the spacer layer into a light-insensitive, dye-forming layer, have been proposed. Known methods to increase reaction efficiency of an oxidized developing agent, by designing a color-forming layer to have a multilayer form, include the method of providing a color-enhancing layer between an emulsion layer and a color-mixing-inhibiting layer (see, e.g., U.S. Pat. No. 5,576,159); the method of providing a coupler-containing layer and a silver halide emulsion layer independently, with these layers being adjacent to each other (see, e.g., JP-A-4-75055 (“JP-A” means unexamined published Japanese patent application) and European Patent No. 0062202); and the method of combining light-sensitive layers and non-light-sensitive dye-forming layers without interposing color-mixing-inhibiting layers among them (see, e.g., U.S. Pat. No. 6,268,116).
A known method to design an intermediate layer, to inhibit color-mixing, to have a multilayer form, on the other hand, is to provide light-insensitive intermediate layers that are different in color-mixing inhibiting property from each other (see, e.g., JP-A-4-110844). However, the above references have no mention of color-mixing-inhibitor-free, non-color-forming intermediate layers.
However, these methods cannot always produce satisfactory effects on ultra-rapid processing. As such, further improvements have been needed in developed-color changes during storage under high humidity, in silver removal characteristics, and in drying characteristics.
As a measure to lessen the loss of oxidized developing agent due to migration from an emulsion layer to an intermediate layer, reduction in size of emulsion grains is also effective. This is because reduction in the reach of an oxidized developing agent can be achieved by adoption of fine-grain emulsions, and can lead to improved reaction efficiency of dye-forming couplers.
Further, it is known (by T. H. James, THE THEORY OF THE PHOTOGRAPHIC PROCESS, 4th. ed., p. 350) that the reaction speeds of dye-forming couplers can be increased, to some extent, by reducing particle sizes of oil-in-water dispersions (emulsified dispersions) containing the dye-forming couplers, to increase surface areas of the particles.
As an emulsifying method, agitation with a dissolver, milling with a colloid mill, and the like are generally adopted. In addition, there is the method of making emulsion grains fine, by making a fluid flow collides with a wall or by making fluid flows collide with each other, to generate impact and shear forces, as in the case of using a Monton-Gaulin homogenizer. However, these methods have the problem of failing to achieve reduction of grain sizes to a value below 0.1 μm.
On the other hand, JP-A-2001-27795 discloses a dispersing method of preparing emulsion grains having sizes of 0.1 μm or below, by use of an ultrahigh-pressure homogenizer.
The methods as mentioned above can produce some effect of improving developed-color densities of silver halide color photographic light-sensitive materials of the type that are reduced in coating amount of silver, but the effect produced is still insufficient. Moreover, it has been revealed that photographic light-sensitive materials having a reduced coating amount of silver had a new problem of developing unevenness of images when they were processed with replenisher-depleted processing solutions after aging. To aim at systems designed with attention to environmental conservation, the replenishment rates of processing solutions are important. As such, there has been a need to solve this new problem.